Supplemental light-emitting diode effects on the growth, fruit quality, and yield of two greenhouse-grown strawberry (Fragaria X ananassa) cultivars
Date
2018
Authors
Stuemky, Andrea, author
Uchanski, Mark, advisor
Newman, Steve, committee member
Thilmany, Dawn, committee member
Journal Title
Journal ISSN
Volume Title
Abstract
Recent interest in off-season, greenhouse-grown food crops using supplemental top lighting(STL) has created opportunities for controlled environmental agriculture (CEA) production of high-value fruit crops such as strawberries (Fragaria X ananassa). Light-emitting diodes (LEDs)can be tailored to specific wavelengths to promote increased production and quality of greenhouse grown crops when used as STL. However, more research is needed to evaluate specific wavelengths of light that can promote increased strawberry fruit production and overall fruit quality in a greenhouse environment. The objectives of this study were to evaluate the effects of three LED STL bars on off-season CEA production of two day-neutral strawberry cultivars, 'Albion' and 'San Andreas'. LED effects on overall vegetative biomass (e.g. stolon production, crown numbers, and leaf area), marketable fruit yield, and fruit quality (e.g. individual fruit weight and soluble solids content (SSC)) were measured during decreasing day lengths of Oct. - Dec.2017 (Exp. 1) and the increasing day lengths of Jan. - April 2018 (Exp. 2). We hypothesized that the addition of STL via three LED bars would increase most measured parameters. Specifically, it was expected that the LED bars with higher densities of blue and red light would produce higher yields and also increase soluble solids content of the berries. The hypotheses were tested by evaluating three LED light top bars (WFR = white far-red, HB = high blue, and LB = low blue) with peaks of blue (450 nm) and red light (665 nm), but at differing photon flux densities (PFD). In these experiments, individual strawberry fruit size and SSC were increased with the use of HB and LB LEDs during the shortening days of Exp. 1. Increased leaf area and crown numbers were also positively affected within all LED treatments (WFR, LB, HB) for 'San Andreas'. The lengthening days of Exp. 2 elicited limited fruiting responses, but stolon production increased within all treatments. In some cases, the two cultivars responded differently to LED STL treatments for leaf area and SSC: 'San Andreas' produced larger leaves and 'Albion' berries having higher SSC than 'San Andreas'. Individual fruit weight of both cultivars increased fruit size in LB and HB treatments in both Exp. 1 and Exp. 2. Our studies indicate that the addition of STL, improved overall strawberry fruit quality and plant growth during shortening day lengths in a greenhouse.